Split AudioRendererMixer::VectorFMAC into VectorMath library.

Prepare the future home for more optimized vector math routines,
specifically FMUL for volume adjustment.

Additionally the FMAC operation will be used for browser side
mixing as well as channel upmixing and downmixing.

BUG=none
TEST=unittests.


Review URL: https://chromiumcodereview.appspot.com/10868037

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@153122 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 59 insertions, 0 deletions

diff --git a/media/base/vector_math.cc b/media/base/vector_math.cc
new file mode 100644
index 0000000..edd95cd
--- /dev/null
+++ b/media/base/vector_math.cc
@@ -0,0 +1,59 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "media/base/vector_math.h"
+#include "media/base/vector_math_testing.h"
+
+#include "base/cpu.h"
+#include "base/logging.h"
+#include "build/build_config.h"
+
+#if defined(ARCH_CPU_X86_FAMILY) && defined(__SSE__)
+#include <xmmintrin.h>
+#endif
+
+namespace media {
+namespace vector_math {
+
+void FMAC(const float src[], float scale, int len, float dest[]) {
+  // Ensure |src| and |dest| are 16-byte aligned.
+  DCHECK_EQ(0u, reinterpret_cast<uintptr_t>(src) & (kRequiredAlignment - 1));
+  DCHECK_EQ(0u, reinterpret_cast<uintptr_t>(dest) & (kRequiredAlignment - 1));
+
+  // Rely on function level static initialization to keep VectorFMACProc
+  // selection thread safe.
+  typedef void (*VectorFMACProc)(const float src[], float scale, int len,
+                                 float dest[]);
+#if defined(ARCH_CPU_X86_FAMILY) && defined(__SSE__)
+  static const VectorFMACProc kVectorFMACProc =
+      base::CPU().has_sse() ? FMAC_SSE : FMAC_C;
+#else
+  static const VectorFMACProc kVectorFMACProc = FMAC_C;
+#endif
+
+  return kVectorFMACProc(src, scale, len, dest);
+}
+
+void FMAC_C(const float src[], float scale, int len, float dest[]) {
+  for (int i = 0; i < len; ++i)
+    dest[i] += src[i] * scale;
+}
+
+#if defined(ARCH_CPU_X86_FAMILY) && defined(__SSE__)
+void FMAC_SSE(const float src[], float scale, int len, float dest[]) {
+  __m128 m_scale = _mm_set_ps1(scale);
+  int rem = len % 4;
+  for (int i = 0; i < len - rem; i += 4) {
+    _mm_store_ps(dest + i, _mm_add_ps(_mm_load_ps(dest + i),
+                 _mm_mul_ps(_mm_load_ps(src + i), m_scale)));
+  }
+
+  // Handle any remaining values that wouldn't fit in an SSE pass.
+  if (rem)
+    FMAC_C(src + len - rem, scale, rem, dest + len - rem);
+}
+#endif
+
+}  // namespace vector_math
+}  // namespace media